Expression of bcl-2-, p53, and Ki-67 and outcome of patients with primary nasopharyngeal carcinomas following DNA-damaging treatment

Identification of fatal outcome in a childhood nasopharyngeal carcinoma patient by protein expression profiling

Nasopharyngeal carcinoma (NPC) is a rare disease in children with good prognosis and high cure rate. Nevertheless, certain patients have an unfavorable prognosis due to development of refractory NPC that is unresponsive to any therapeutic strategies. The current study studies a case of a 17 years-old female with non-keratinizing NPC type IIb (T2N0M0), who passed away as a consequence of resistance to chemo-, radio- and β-interferon therapy, and to an allogenic stem cell transplantation. In order to identify factors that lead to treatment failure and fatal outcome, immunohistochemical analyses of different tumor biomarkers and hierarchical cluster analysis were performed and compared with those of eight other patients with NPC who experienced complete remission following conventional therapy. Hierarchical cluster analysis of the immunohistochemical results clearly demonstrated that staining for immunological factors (CD4, CD8 and CD56) distinguished this patient from the others. To further investigate a potential role of the immune system, lymphocytic infiltration was assessed in tumor tissue by evaluation of hematoxylin and eosin-stained tumor sections. Indeed, no tumor infiltrating lymphocytes (TILs) were observed in this NPC case, while 7 out of 8 of the other NPC samples contained variable TIL amounts. The view that immunodeficiency of the patient may be a factor in the fatal outcome of treatment is supported by the fact that this patient with NPC was not positive for Epstein-Barr virus markers and also infected by several other viruses and fungi (herpes simplex virus, human herpes virus 6, Varicella zoster virus, and Candida). In conclusion, the investigation of rare NPC cases with poor prognosis may provide an improved understanding of the molecular mechanisms involved in refractory tumors and identification of novel potential therapeutic targets for NPC in the future.

Correlation of microvascular density and proliferation index in undifferentiated nasopharyngeal carcinoma

Background: Undifferentiated nasopharyngeal carcinoma is a highly malignant tumor with an endemic distribution. Several histologic parameters have been studied to provide prognostic information for patient management. Both proliferation index and microvascular density are commonly determined on such tumors, but the relationship between these two parameters has not been studied fully. Objectives: Determine the association between microvascular density and cellular proliferation in undifferentiated nasopharyngeal carcinoma. Methods: A series of 60 cases were studied in patients of Southeast Asian origin. Cellular proliferation was determined using Ki67 immunostaining, and vessel proliferation using CD31 immunostaining in terms of areas of increased staining (‘hot spots’). Ki67 results were scored on a scale of 0-4+ and CD31 results as a microvascular density/mm2. Results: The mean of the microvascular density was 22/mm2 in the Ki67-negative group (25 cases). In the Ki67- positive group (35 cases), the mean was 35/mm2. The difference between the positive and negative group was statistically significant (p <0.001). Microvascular density significantly increased as the Ki67 score increased (p<0.001). However, the ‘hot spots’ for microvascular density in tissue sections did not correspond to areas of increased cellular proliferation. Conclusion: Pathologists usually determine only one of these two prognostic factors when dealing with undifferentiated nasopharyngeal carcinoma. The proliferation index is suggested because it is easier to perform and can be done on small biopsies not to contain enough surface area for microvascular density determination.

Increased Expression of Cullin 3 in Nasopharyngeal Carcinoma and Knockdown Inhibits Proliferation and Invasion

This study aimed to investigate the clinical significance of cullin 3 expression in nasopharyngeal carcinoma (NPC), as well as to explore the regulatory mechanism of cullin 3 underlying the growth and metastasis of NPC cells. Our findings showed that the expression levels of cullin 3 were significantly increased in both NPC tissues and cell lines. A strong positive correlation was found between cullin 3 expression and the Ki-67-based proliferation index in NPC tissues. Moreover, cullin 3 overexpression was correlated with local relapse and distant metastasis in NPC patients. In vitro experiments showed that knockdown of cullin 3 caused a significant reduction in the proliferation of NPC cells, probably by inducing cell cycle arrest. In addition, downregulation of cullin 3 inhibited colony formation and the migratory and invasive capacities of NPC cells. The expression levels of PCNA and epithelial-to-mesenchymal transition (EMT)-related proteins were also meditated by cullin 3 in NPC cells. Based on these findings, we demonstrated that cullin 3 plays a promoting role in the malignant progression of NPC and suggest that the cullin 3-based ubiquitin proteasome pathway may be used as a promising therapeutic target for NPC.

ERCC1 Cys8092Ala and XRCC1 Arg399Gln polymorphisms predict progression-free survival after curative radiotherapy for nasopharyngeal carcinoma

Background

Single nucleotide polymorphisms (SNPs) in DNA repair genes can alter gene expression and activity and affect response to cancer treatment and, correspondingly, survival. The present study was designed to evaluate the utility of the XRCC1 Arg399Gln and ERCC1 Cys8092Ala SNPs, measured in pretreatment biopsy samples, as predictors of response to radiotherapy in patients with non-metastatic nasopharyngeal carcinoma (NPC).

Materials and methods

The study included 75 consecutive patients with stage II-IVA-B NPC. XRCC1 Arg399Glu and ERCC1 Cys8092Ala SNPs were identified from paraffin-embedded biopsy specimens via Sanger sequencing. Expression of p53 and pAkt protein was analyzed by immunohistochemical staining. Potential relationships between genetic polymorphisms and progression-free survival (PFS) were analyzed by using a Cox proportional hazards model, the Kaplan-Meier method, and the log-rank test.

Results

Multivariate analysis showed that carriers of the ERCC1 8092 Ala/Ala genotype [hazard ratio (HR) 1.882; 95% confidence interval (CI) 1.031–3.438; P = 0.039] and heavy smokers (≥20 pack-years) carrying the XRCC1 Arg/Arg genotype (HR 2.019; 95% CI 1.010–4.036; P = 0.047) had significantly lower PFS rates. Moreover, combined positive expression of p53 and pAkt led to significantly increased PFS in subgroups carrying the XRCC1 Gln allele (HR 7.057; 95% CI 2.073–24.021; P = 0.002) or the ERCC1 Cys allele (HR 2.568; 95% CI 1.056–6.248; P = 0.038).

Conclusions

The ERCC1 Cys8092Ala polymorphism is an independent predictor of response to radiotherapy for NPC, and the XRCC1 Arg399Glu mutation combined with smoking status seems to predict PFS as well. Our results further suggest a possible correlation between these genetic polymorphisms and p53 protein status on survival.

Expression of pAkt affects p53 codon 72 polymorphism-based prediction of response to radiotherapy in nasopharyngeal carcinoma

Background

Codon 72 (Arg/Pro), the most frequently studied single nucleotide polymorphism (SNP) of p53 to date, is associated with the ability of the gene to induce cell apoptosis. The PI3K/Akt pathway plays an essential role in the transcriptional activation function of p53, and is an important factor in radiotherapy resistance. The present study was designed to evaluate the prediction of response to radiotherapy based on p53 codon 72 SNP and pAkt expression in biopsy specimens of locoregional nasopharyngeal carcinoma (NPC) before treatment.

Materials and methods

In total, 75 consecutive patients with locoregional NPC were enrolled. The p53 codon 72 SNP was identified from retrospectively collected paraffin-embedded biopsy specimens using Sanger sequencing. Expression patterns of p53, p21, 14-3-3σ, and pAkt proteins were investigated using immunohistochemical analyses. The effects of genetic polymorphisms and protein expression on progression-free survival (PFS) were evaluated using the Cox proportional hazards model, Kaplan–Meier method, and log-rank test.

Results

The p53 codon 72 Pro/Pro carriers showed lower risk of disease progression (local recurrence and distant metastases) (HR: 0.300; 95% CI: 0.092–0.983; p=0.047). However, this association between the p53 codon 72 polymorphism and PFS was not significant in the pAkt-positive subgroup. No association was observed between protein expression of p53, p21 or 14-3-3σ and p53 codon72 polymorphisms. Notably, positive expression of p53 protein appeared to be correlated with poorer PFS among patients diagnosed as local regional lymph node metastasis (N+) before treatment (p=0.032).

Conclusions

The p53 codon 72 Pro/Pro genotype may be an effective independent prognostic marker for better outcome in patients with locoregional NPC. Based on the current findings, we hypothesize that pAkt weakens the predictive value of p53 codon 72 SNP in NPC. A combination of positive p53 protein expression and local regional lymph node metastasis may additionally be predictive of high risk of disease progression.

Immunohistochemical study identifying prognostic biomolecular markers in nasopharyngeal carcinoma treated by radiotherapy

BACKGROUND

We evaluated the predictive significance of 14 reported markers using immunohistochemical study in nasopharyngeal carcinoma.

METHODS

Immunohistochemical stainings were done in 38 patients for Met, cyclooxygenase-2 (COX-2), nm23-H1, epidermal growth factor receptor (EGFR), p63, early growth response factor 1 (Egr1), chromosome segregation 1-like (CSE1L), cathepsin-D (aspartyl protease), C-erbB2, p53, signal transducers and activators of transcription (STAT3/STAT5), CD138 (Syndecan-1), and LIN28 with the usual methods.

RESULTS

The median follow-up time was 30 months (11-83 months). High Met and CD138 expression were statistically significant negative prognostic factors on survival. The expression of Egr1 had a positive prognostic effect on survival. The combined score of these 3 markers, Met plus CD138 minus Egr1, was a strong prognostic factor. The median survival curve was distinctly separated in accord with this combined score. No prognostic value was revealed in COX-2, nm23-H1, EGFR, p63, CSE1L, cathepsin-D, C-erbB2, p53, STAT3, STAT5, and LIN28.

CONCLUSIONS

The combined score of these markers could be used to stratify biomolecular risk groups.

Expression modes and clinical manifestations of latent membrane protein 1, Ki-67, cyclin-B1, and epidermal growth factor receptor in nonendemic nasopharyngeal carcinoma

BACKGROUND

We aimed to identify clinical significance of latent membrane protein 1 (LMP1), Ki-67, cyclin-B1, and epidermal growth factor receptor (EGFR), in nonendemic nasopharyngeal carcinoma (NPC).

METHODS

The relation between expression of the markers in 45 NPC specimens and clinicopathological and survival variables was statistically analyzed.

RESULTS

LMP1 was present in 33% of the tumors, and its presence was associated with advanced nodal and disease stages. Overexpression was defined as labeling index > or = median value for Ki-67, > or = 15% for cyclin-B1, and > or =50% for EGFR, and it was displayed in 50%, 55%, and 80% of the specimens, respectively. Strong EGFR staining intensity and not overexpression of the 3 markers was the variable with statistically significant impact on treatment outcomes in terms of worse local and locoregional tumor control rates.

CONCLUSIONS

Our results suggest that the evaluation of EGFR staining intensity in patients with NPC may identify a subgroup of patients with poor prognosis.

The prognostic value of proliferating cell nuclear antigen (PCNA) and p53 protein expression in patients with advanced nasopharyngeal carcinoma

CONCLUSION

p53 protein and proliferating cell nuclear antigen (PCNA) were not ideal prognostic indicators in advanced nasopharyngeal carcinoma (NPC). Further investigation in searching for other potential biomarkers is needed to enhance the prediction of treatment outcome.

OBJECTIVE

To assess the prognostic significance of p53 protein and PCNA expression in patients with advanced NPC.

PATIENTS AND METHODS

This study included 46 patients with advanced NPC who had received treatment and regular follow-up for at least 5 years. We used immunohistochemistry (IHC) staining to assess p53 protein expression and PCNA labeling index, and correlate them with pathological subtypes, TNM stage, the presence of locoregional recurrence, and 5-year survival rate.

RESULTS

p53 nuclear staining was positive in 32 patients (69.6%). All cases had positive PCNA nuclear staining with labeling index (LI) ranging from 6.5% to 92.9% (mean 53.4%). Only advanced T stage was found to be associated with high PCNA LI. Overexpression of p53 and PCNA LI had no impact on 5-year survival in this study group.

Correlation between proliferating cell nuclear antigen and p53 protein expression and 5-year survival rate in nasopharyngeal carcinoma

PURPOSE

To assess the prognostic significance of p53 protein and proliferating cell nuclear antigen (PCNA) expression in nasopharyngeal carcinoma.

MATERIALS AND METHODS

This study included 79 patients who had received treatment and regular follow-up for at least 5 years at a single institute. We used immunohistochemistry staining to assess p53 protein expression and PCNA labeling index (LI). Analyses were conducted on the association between each of the 2 biomarkers and pathological subtypes, TNM stage, the presence of locoregional recurrence, and 5-year survival rate.

RESULTS

p53 protein nuclear staining was positive in 49 patients (62%). The mean PCNA LI was 55.6%, ranging from 3.35% to 92.9%. High PCNA LI (>55.6%) might contribute to higher 5-year survival rate, but it did not reach statistical significance (P = .09). Positive p53 protein staining and low PCNA LI were associated with the presence of locoregional recurrence. No statistical significance was found between p53 protein expression and PCNA LI and pathological subtypes and TNM stage.

CONCLUSION

p53 protein and PCNA LI were not an ideal prognostic indicator in predicting 5-year survival rate in nasopharyngeal carcinoma. Future work will direct toward searching for other potential biomarkers with the hope to reinforce prediction of prognosis.

Pediatric nasopharyngeal carcinoma: better prognosis and increased c-Kit expression as compared to adults

INTRODUCTION

Nasopharyngeal carcinoma (NPC) in children is distinguishable from the adult form by its close association with Epstein-Barr virus (EBV) infection, a higher rate of undifferentiated histology, and a greater incidence of advanced locoregional disease.

PATIENTS AND METHODS

Sixteen NPC patients, < or =20 years of age were identified from our 1976-2001 tumor registry records. Clinical stage, treatment, recurrence, and survival were evaluated. Sections were stained by immunohistochemistry for p53, Bcl-2, Ki67, and c-Kit and by in situ hybridization for EBER. Obtained data were compared to 32 adult patients. All patients had undifferentiated or non-keratinizing NPC.

RESULTS

EBER was positive in 100% of children, compared to 90% of adults. Comparing children to adults, median Ki67 index was 49% and 30%, p53 positive tumors were 69% and 94%, positive Bcl-2 was 63% and 72%, and positive c-Kit was 88% and 28%, respectively.

CONCLUSION

No parameter had significant predictive values for survival, although c-Kit expression had a trend for better prognosis in the pediatric group. By univariate analysis of all 48 cases, positive c-Kit was associated with better survival (P = 0.029), largely due to the better survival of the pediatric group. By multivariate analysis, increased stage (P = 0.006) and older age (P = 0.044) correlated with worse prognosis.

Inducible nitric oxide synthase and bcl-2 expression in nasopharyngeal cancer: correlation with outcome of patients after radiotherapy

PURPOSE

The expression of inducible nitric oxide synthase (iNOS) and bcl-2 proteins was evaluated and the prognostic significance determined in nasopharyngeal cancer (NPC) patients treated by radiotherapy.

METHODS AND MATERIALS

Tissue sections from 55 patients with NPC were assessed for iNOS and bcl-2 protein expression by immunohistochemistry, immunoelectron microscopy, and in situ hybridization before treatment. The markers were correlated with apoptosis (detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay) and clinicopathologic parameters.

RESULTS

All NPC sections exhibited positive iNOS and bcl-2 immunoreactivity, with a mean percentage of 6.24% +/- 0.58% and 17.09% +/- 2.48%, respectively. A significant positive correlation was observed between iNOS expression and the apoptotic index (p < 0.0001, Pearson's r = 0.8518), and bcl-2 expression correlated inversely with apoptosis (p = 0.0001; Pearson's r = -0.6170). A significant inverse correlation was found between iNOS and bcl-2 immunoreactivity (p < 0.0001, Pearson's r = -0.7144). Bcl-2 but not iNOS expression was associated with the stage of the tumor according to the criteria of the American Joint Committee on Cancer (1997) (p < 0.0001). Patients who had recurrence of the tumor and metastasis after radiotherapy had a lower expression of iNOS (p = 0.014 and p = 0.035, respectively), although overall survival was not significantly different statistically. Higher bcl-2 expression was also associated with local tumor recurrence (p = 0.005) but not with metastasis or overall survival.

CONCLUSION

It appears that iNOS and bcl-2 expression may be potentially useful biomarkers for predicting the outcome of radiotherapy in NPC patients.

Novel gene therapy approach for nasopharyngeal carcinoma

This article will provide an overview on the status of cancer gene therapy, focussed specifically on its potential application in nasopharyngeal carcinoma (NPC). The concepts and strategies behind the design of therapeutic targets such as p53, p16, and death genes will be described. One of the major challenges in cancer gene therapy is tumor-specific expression of therapeutic genes, and a transcriptional targeting approach will be reviewed, in reference to NPC. Specifically, the ability to exploit the presence of Epstein-Barr virus (EBV) will be emphasized. The currently available preclinical data on genetic therapeutic approaches for NPC will be reviewed, and an outline for its future role in management of NPC, in conjunction with existing cytotoxic modalities of ionizing radiation and chemotherapy will be provided.

Differential expression of the suppressor PML and Ki-67 identifies three subtypes of human nasopharyngeal carcinoma

The promyelocytic leukaemia (PML) gene, which encodes a transformation and growth suppressor, was found to regulate transcription and apoptosis. PML was first identified at the chromosomal translocation break-points t(15;17) of acute promyelocytic leukaemia and the gene product may mediate cell-cycle control and apoptosis. PML was found to interact with the co-transactivator CREB binding protein (CBP) and the apoptotic-modulator Bax. To determine if PML, CBP and Bax may be involved in solid tumours, such as the nasopharyngeal carcinoma (NPC), a rare neoplasia that is prevalent in Southern China, the expression of these proteins and the proliferation marker Ki-67 was analysed by immunohistochemical staining. Expression of PML in the PML-oncogenic domain (POD) or nuclear bodies in most NPC was inversely correlated with the expression of Ki-67. In addition, based on PML expression patterns in NPC three subtypes could be identified, namely, Subtype-1, with strong PML expression in POD structures and with low Ki-67 staining; Subtype-2, where PML was expressed in a homogeneously diffused pattern, but with a low intensity in the tumour cells; while Ki-67 was expressed in a moderate number of cells and Subtype-3, where the majority of tumour cells were PML-negative, while a considerable number of tumour cells were strongly labelled with Ki-67. Furthermore, CBP was present in most of the NPC cells with moderate-strong nuclear staining, while the expression in non-tumour cells were relatively weak. However, there was no direct correlation between PML and CBP expression in the NPC examined. In addition, there was low or no expression of Bax in the NP and NPC. This is, to our knowledge, the first report describing PML and CBP expression in NPC and our data strongly suggests that PML and CBP, but not Bax, may play a role in the transformed phenotypes of NPC.

Molecular pathology parameters in human nasopharyngeal carcinoma

BACKGROUND

To derive a better understanding of the biologic behavior of nasopharyngeal carcinoma (NPC), the authors evaluated a number of molecular variables to address the hypothesis that p53 dysfunction in NPC is associated with Epstein-Barr virus (EBV), increased tumor angiogenesis, lower likelihood of apoptosis, and poorer clinical outcome.

MATERIALS

The biopsy samples from 87 NPC patients were obtained and sections were made to detect EBV, using in-situ hybridization; the authors used immunohistochemistry to assess p53, p21(WAF1/CIP1) expression, and microvessel density count (MVD). In situ end labelling was used to evaluate apoptosis and necrosis. Analyses were conducted on the association between each of these variables as well as clinical outcome, including survival and local control.

RESULTS

There was a highly significant association between EBV-encoded RNA (EBER) positivity with p53 over-expression in that only 1 out of 32 p53 over-expressing tumors was EBER negative, as opposed to 19 out of 48 p53 negative tumors being EBER negative (P = 0.001). In addition, EBER positivity was highly associated with World Health Organization (WHO) type 3 NPC, Asian/Chinese ethnicity, a lower apoptotic index, and p21 over-expression. p53 over-expression was associated with a higher MVD count. Controlling for age and nodal status, EBER positivity was associated with both improved overall survival (P = 0.02), and disease-free survival (P = 0.04). In contrast, the presence of tumor necrosis was associated with an inferior local control (P = 0.03).

CONCLUSION

p53 protein was over-expressed in approximately one third of NPC samples in the current study, and this correlated significantly with the presence of EBER. Epstein-Barr virus status was also associated with WHO type 3 NPC, Asian/Chinese ethnicity, and induction of p21. The presence of EBV appeared to predict for improved survival, the mechanism of which remains to be elucidated in this biologically complex disease.

Important prognostic factors in patients with skull base erosion from nasopharyngeal carcinoma after radiotherapy

PURPOSE

To evaluate the long-term outcome and prognostic factors in patients with skull base erosion from nasopharyngeal carcinoma after initial radiotherapy (RT).

METHODS AND MATERIALS

From January 1985 to December 1986, 100 patients (71 males, 29 females) with a diagnosis of nasopharyngeal carcinoma were found on computed tomography (CT) to have skull base erosion. The mean age was 41 years (range 16-66). Ninety-six patients had World Health Organization type III undifferentiated carcinoma, and 4 had type I. The metastatic workup, including chest radiography, liver ultrasound scanning, and liver function test was negative. All patients underwent external beam RT (EBRT) alone to 66-80 Gy during 6-8 weeks. A daily fraction size of 2 Gy was delivered using 60Co or a linear accelerator. No patient received chemotherapy. All patients were followed at regular intervals after irradiation. The median follow-up was 22.3 months (range 2-174). Survival of the cohort was computed by the Kaplan-Meier method. The potential prognostic factors of survival were examined. Multivariate analyses were performed using the Cox regression model.

RESULTS

The 1, 2, 5, and 10-year overall survival rate for the cohort was 79%, 41%, 27%, and 13%, respectively. However, the subgroup of patients with both anterior cranial nerve (I-VIII) and posterior cranial nerve (IX-XII) involvement had a 5-year survival of only 7.7%. A difference in the time course of local recurrence and distant metastasis was observed. Both local recurrence and distant metastasis often occurred within the first 2 years after RT. However, local relapse continued to occur after 5 years. In contrast, no additional distant metastases were found after 5 years. The causes of death included local recurrence (n = 59), distant metastasis (n = 21), both local recurrence and distant metastasis (n = 1), and unrelated causes (n = 5). After multivariate analysis, complete recovery of cranial nerve involvement, cranial nerve palsy, and headache after irradiation were found to be independent prognostic factors in this cohort.

CONCLUSIONS

We present one of the longest follow-ups of patients with nasopharyngeal carcinoma invading the skull base. Our results demonstrate the importance of cranial nerve involvement, recovery of headache, and cranial nerve palsy. These factors should be carefully evaluated from the history, physical examination, and imaging studies. A subgroup of patients with skull base involvement had long-term survival after RT alone. The findings of this study are important as a yardstick against which more aggressive strategies, such as combined radiochemotherapy and altered fractionation RT can be compared.

Clinical implications of biomarkers in head and neck cancer

The term biomarker refers to a host of biologic factors found within a tumor or other clinical specimen that can be used to assess the tumor in some way. Biomarkers have many potential clinical applications. Before they are used in actual clinical settings, however, they must be carefully validated. The literature contains many reports of this ongoing work related to head and neck squamous cell carcinoma. Candidate biomarkers for this disease include the p53 gene and its protein; microsatellite regions throughout the genome; human papillomavirus; proteins involved in cellular proliferation, apoptosis, angiogenesis, and intracellular adhesion; epithelial growth factor receptor; and various measures of immune response to cancer. The best new evidence for the validity of each of these candidates is critiqued in this review.

Locally advanced nasopharyngeal cancer

The Head and Neck Cancer Intergroup phase III clinical trial (Int 0099) for patients with locally advanced, squamous cell carcinomas (SCC) of the nasopharynx (or NPC) has been recently completed in the United States. The results of this study have defined the new standard of treatment for the group of patients studied. Patients with untreated, locally advanced stages III and IV NPC were randomized to a conventional course of radiation, or to radiation given concurrently with chemotherapy followed by three courses of combination chemotherapy. The 3-year progression-free survival (PFS) and overall survival (OS) were 24% versus 69% (P < 0.001) and 46% versus 76% (P < 0.001) for the control and experimental groups, respectively. Recent updates of these survival figures show that they have not changed appreciably. The considerable improvement in OS versus PFS for the patient group receiving radiation alone is accounted for primarily by re-treatment with concurrent radiation-chemotherapy, combination chemotherapy, and isolated salvage neck dissections. Highly significant differences in local control (41% vs 14%) and distant metastases (35% vs 13%) were demonstrated in favor of the chemoradiation treatment arm. The median age for these patients was 51 years, with a 2:1 male to female ratio. Although many patients had a significant history of tobacco exposure with or without alcohol use or abuse, only 24% had keratinizing or well-differentiated squamous (World Health Organization I) type tumors. Whether these results can be extrapolated to the more common Asian variety (WHO II and III) of advanced NPC must be addressed in future clinical trials.